US2720557A - Time division pulse code modulation system employing continuous coding tube - Google Patents

Time division pulse code modulation system employing continuous coding tube Download PDF

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Publication number
US2720557A
US2720557A US67211A US6721148A US2720557A US 2720557 A US2720557 A US 2720557A US 67211 A US67211 A US 67211A US 6721148 A US6721148 A US 6721148A US 2720557 A US2720557 A US 2720557A
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US
United States
Prior art keywords
pulses
time division
tube
modulation system
code
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US67211A
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English (en)
Inventor
William M Goodall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to FR1003982D priority Critical patent/FR1003982A/fr
Priority to NL106021D priority patent/NL106021C/xx
Priority to BE492937D priority patent/BE492937A/xx
Priority to NL727202264A priority patent/NL150593B/xx
Priority to US67211A priority patent/US2720557A/en
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to DEW574A priority patent/DE830810C/de
Priority to CH297629D priority patent/CH297629A/de
Priority to GB32718/49A priority patent/GB679737A/en
Application granted granted Critical
Publication of US2720557A publication Critical patent/US2720557A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M1/00—Analogue/digital conversion; Digital/analogue conversion
    • H03M1/12—Analogue/digital converters
    • H03M1/14—Conversion in steps with each step involving the same or a different conversion means and delivering more than one bit

Definitions

  • This invention relates to a communication system and more particularly to a communication system in which complex wave forms are transmitted by code groups of pulses transmitted at rapidly recurring instants of time.
  • An object of this invention is to provide an improved and simplied means and methods for representing complex wave forms by means of code groups of different signaling conditions which improved means and methods are capable of operating at high speed.
  • Another object of this invention is to provide improved decoding equipment which is capable of operating at high speed for recovering the complex Wave form represented by coded groups of different signaling conditions of short duration occurring in rapid succession.
  • a feature of this invention relates to a cathode-ray tube which is capable of substantially continuously and instantaneously representing a complex wave form by a complete code group of different signaling conditions.
  • the cathode-ray tube is of a type which is provided with a target and electrodes which at substantially all times have applied to them electrical conditions representing a complete code group, determined by the instantaneous amplitude of the complex wave form.
  • Another feature of this invention relates to a cathoderay coding tube wherein the coding target is arranged to cause certain codes, i. e., the end codes, to be extended so that these codes will be formed when the applied signal exceeds the operating range of the tube.
  • Another feature of this invention relates to circuits and apparatus and methods of changing code groups of pulses of one code into code groups of pulses of a diierent code.
  • Another feature of this invention relates to circuits, apparatus and methods of changing from a second coded group of pulses back to the first code group of pulses.
  • Another feature of this invention relates to methods, circuits and apparatus for periodically checking and automatically setting the translating circuits.
  • Another feature of this invention relates to equipment for changing a code group of signaling conditions simultaneously present at an instant of time into a code group of signaling conditions occurring one after another in sequence by means of transmitting the signaling conditions through delay networks, lines or devices having different delay intervals.
  • Another feature of this invention is to combine pulses of different signaling conditions received in sequence one after another into a single pulse by transmitting the various pulses received through delay networks, lines or devices of different delay intervals so that pulses arrive at the output of the delay devices substantially simultaneously.
  • a complex wave form is employed to control the generation of code signals.
  • the magnitude or amplitude ICC of a complex signaling wave such as a speech wave, telegraph wave, or other complex signaling wave is represented by means of code groups of signals each signal of which may comprise any number of a plurality of frequency division multiplex signals, time division multiplex signals, or different signaling conditions.
  • each code group is of a uniform number of different signals or a predetermined number of pulses in which each of the signals or pulses may comprise signaling conditions of any of a plurality of different signaling conditions.
  • code groups may comprise live or less signals or pulses and that each pulse or signal may com* prise either one of the two signaling conditions and may be transmitted during the time assigned to the various pulses or pulse positions.
  • any suitable code may be employed wherein the different code groups are assigned to represent the different amplitudes of the complex Wave form.
  • the coding and decoding equipment is arranged to generate and respond to the binary code in which each of the signals or pulses represents or is analogous to a digital position of a binary number and one signaling condition represents one magnitude of a digit and the other signaling condition represents another magnitude of a digit.
  • pulses of one character are frequently called marking pulses, on pulses, or current pulses, while the pulses of the other signaling condition are frequently called spacing pulses, olf pulses, or pulses of no current. Sometimes these two pulses are called positive pulses and negative pulses.
  • the signals or signaling conditions as they are being transmitted through the various circuits and apparatus of the system may be represented by different signaling conditions. It is frequently most convenient to refer to each pulse as marking or spacing signals.
  • the code groups of signals may be all generated substantially instantaneously under control of the complex wave or they may be generated at predetermined times in rapid succession so that the amplitude of the complex signaling wave can be represented by a group of signals or pulses occurring at a plurality of rapidly recurring instants of time.
  • the rapidity of the recurrences of the code groups representing any complex signaling Wave determines the highest frequency component of the signaling wave which may be transmitted over the system. In general, the frequency of this component is somewhat less than half the highest recurrence rate of transmitted pulse or signal groups representing the amplitude of the complex wave.
  • the coding equipment should generate complete code groups of pulses or signal conditions at a rate of at least 12,000 codes each second.
  • Fig. 1 shows the manner in which Figs. 4 through 13 are arranged adjacent one another;
  • Figs. 2 and 3 show in outline form the various elements of an exemplary system embodying the present invention.
  • Fig. 2 shows the various elements in the manner in which they cooperate one with another at the transmitting station or near the end of the system while
  • Fig. 3 shows the manner in which the various elements of the system cooperate with each other at the receiving or distant end of the system.
  • the equipment and apparatus required for the transmission of the signals or complex wave form in one direction only is shown in the drawing.
  • FIG. 4 through 13 when positioned as shown in Fig. l show in detail the various circuits and the method in which they cooperate to form an exemplary system embodying the present invention
  • Figs. 5 through 9 show in detail the equipment at the transmitting station while Figs. l0 through 13 show in detail the circuits at the receiving station;
  • Fig. 14 shows a perspective of an exemplary cathoderay tube embodying the present invention which is suitable for use as a coding device at the transmitting station;
  • Figs. 15 through 2l show graphs of voltages and currents at various positions in the system illustrating the mode of operation of the various circuits and the manners in which they cooperate with each other.
  • Figs 2 and 3 show in outline form the various cornponent circuits in the manner in which they cooperate to form an exemplary system in accordance with the present invention.
  • Fig. 2 shows the transmitting equipment including the coding apparatus.
  • Fig. 3 shows the corresponding equipment at the receiving terminal including the receiving synchronizing and controlling equipment, and the decoding apparatus and equipment for reconstructing the original communication signals or Wave forms.
  • 210 represents the source of signal which is usually a microphone for voice signals, but may include any other suitable source of signals including telegraph signals, picture signals, facsimile signals, frequency division multiplex signals, etc.
  • the source of signals 210 is connected to the terminal equipment 211 by means of any suitable type of transmission circuits and paths including telephone open-wire lines, cable circuits, carrier Current communication paths, radio paths, toll circuits, etc.
  • the terminal equipment 211 may include various types of switching equipment for establishing communication paths from the source 501 to the terminal equipment in the exemplary system set forth herein. Each of these systems as well as the associated equipment operates in its usual and well understood manner so that it is not necessary to repeat a description of the operation thereof herein.
  • the output ot the terminal equipment S02 is transmitted through switches 503 and 213, which switches when set in the position shown in the drawing, cause signaling currents of a complex signaling wave form such as speech currents to be transmitted from the transmitter or signal source 501 through the terminal equipment 502 and switches 503 and 213 to the coding and differentiating circuit 214.
  • Coding and diiierentiating circuit 214 comprises a coding tube 250 to which the signaling wave is applied.
  • a plurality of voltages are applied to the output electrodes of the tube.
  • the tube is provided with a plurality of these electrodes which are connected in a circuit such that they either have one or the other of two different voltages applied to them depending upon the amplitude of the applied signaling wave.
  • the combination of voltages applied to the output electrodes of the tube correspond to the magnitude of the instantaneous voltage applied to the input of the coding tube.
  • the voltages appearing on the output electrodes are in accordance with the input voltage and a predetermined code.
  • the output voltages are applied substantially simultaneously to all of the output electrodes of the tube so that the output of the tube at all times represents the instantaneous amplitude of a complex signaling wave.
  • a plurality of delay devices 251 through 255 are connected to the output of the coding tube 250. These delay devices all have different delay intervals. In a specitic embodiment of the invention the delay intervals between the various delay devices are equal to the time allowed to each code pulse or to interval multiples thereof. The delay of the various delay devices may be arranged in any desired predetermining order in which the voltage characteristic of the respective output electrodes of the coding tube 250 are transmitted over the communication system.
  • the voltages representing the various codes are applied substantially simultaneously to the input of these delay devices but the voltages appear at the output terminals of these delay devices in succession.
  • the devices may be arranged in any order so that the pulses follow one another in succession at the output terminals of the adjacent ones of said devices. However, when desired, these delay devices may be arranged in any desired order.
  • the distributor circuit 270 comprises a portion of the multiplex control equipment 215 at the transmitting station.
  • This system also includes a code element timing circuit 271 and pulse forming and timing circuit 272.
  • the synchronizing and multiplex system 215 also includes the code element timing circuit 271 and a pulse shaping and tuning circuit 272.
  • switches 256 through 260, inclusive are moved to positions opposite to the positions shown in the drawing.
  • the output of delay devices 251 through 255 must tirst pass through the respective translating circuits 261 through 265 which circuits cause a pulse to be transmitted each time the output of each delay device 251 through 255 changes in character.
  • These pulses are then transmitted to the transmitting distributor 270 when the switches 256 through 260 are moved to the positions opposite to the positions shown in the drawing. Thereafter, the pulses are transmitted over the system substantially the same as described herein.
  • a sampling circuit 286 has also been provided and when switches 503 and 213 are moved to their positions opposite to the positions shown in the drawing the signals from the terminal equipment 502 are first transmitted to the sampling circuit 230. Under these circumstances,
  • Y signals from the terminal equipment are first applied to the sampling circuit 230 which causes an output voltage to be developed across its output terminals which voltage

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
  • Particle Accelerators (AREA)
  • Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
  • X-Ray Techniques (AREA)
  • Dc Digital Transmission (AREA)
US67211A 1948-12-24 1948-12-24 Time division pulse code modulation system employing continuous coding tube Expired - Lifetime US2720557A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
BE492937D BE492937A (sk) 1948-12-24
NL727202264A NL150593B (nl) 1948-12-24 Inrichting voor het tijdsgetrouw automatisch uitlezen van diagrammen.
FR1003982D FR1003982A (sk) 1948-12-24
NL106021D NL106021C (sk) 1948-12-24
US67211A US2720557A (en) 1948-12-24 1948-12-24 Time division pulse code modulation system employing continuous coding tube
DEW574A DE830810C (de) 1948-12-24 1949-12-08 Nachrichtenuebermittlungssystem fuer die Sendung und den Empfang von Impulsschluesselkombinationen
CH297629D CH297629A (de) 1948-12-24 1949-12-16 Fernmeldeanlage mit Impulscodemodulation.
GB32718/49A GB679737A (en) 1948-12-24 1949-12-21 Improvements in or relating to signal transmission systems using pulse code modulation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US67211A US2720557A (en) 1948-12-24 1948-12-24 Time division pulse code modulation system employing continuous coding tube

Publications (1)

Publication Number Publication Date
US2720557A true US2720557A (en) 1955-10-11

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US67211A Expired - Lifetime US2720557A (en) 1948-12-24 1948-12-24 Time division pulse code modulation system employing continuous coding tube

Country Status (7)

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US (1) US2720557A (sk)
BE (1) BE492937A (sk)
CH (1) CH297629A (sk)
DE (1) DE830810C (sk)
FR (1) FR1003982A (sk)
GB (1) GB679737A (sk)
NL (2) NL106021C (sk)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3030614A (en) * 1959-09-03 1962-04-17 Space General Corp Telemetry system
US3204030A (en) * 1961-01-23 1965-08-31 Rca Corp Acoustic apparatus for encoding sound
US4179657A (en) * 1958-08-28 1979-12-18 The United States Of America As Represented By The Secretary Of The Air Force Anti-jamming communication system

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL111778C (sk) * 1952-04-09

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2185693A (en) * 1938-02-25 1940-01-02 Bell Telephone Labor Inc Multiplex signaling system
US2213938A (en) * 1938-07-26 1940-09-03 Bell Telephone Labor Inc Multiplex signaling with phase discrimination
US2412350A (en) * 1943-05-10 1946-12-10 Curtis Engineering Company Multiple scale, multiple function instrument indicating system
US2418116A (en) * 1943-12-20 1947-04-01 Standard Telephones Cables Ltd Multiplex synchronizing system
US2449467A (en) * 1944-09-16 1948-09-14 Bell Telephone Labor Inc Communication system employing pulse code modulation
US2451044A (en) * 1945-07-09 1948-10-12 Bell Telephone Labor Inc Communication system employing pulse code modulation
US2453461A (en) * 1946-06-19 1948-11-09 Bell Telephone Labor Inc Code modulation communication system
US2453454A (en) * 1946-08-31 1948-11-09 Bell Telephone Labor Inc Coder for code modulation transmission
US2478919A (en) * 1943-07-17 1949-08-16 Rca Corp Pulse type multiplex communication system
US2581426A (en) * 1939-03-24 1952-01-08 Creed & Co Ltd Arrangement for receiving telegraph impulses
US2603714A (en) * 1948-09-01 1952-07-15 Bell Telephone Labor Inc Percentage time division multiplex for pulse code modulation

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2185693A (en) * 1938-02-25 1940-01-02 Bell Telephone Labor Inc Multiplex signaling system
US2213938A (en) * 1938-07-26 1940-09-03 Bell Telephone Labor Inc Multiplex signaling with phase discrimination
US2581426A (en) * 1939-03-24 1952-01-08 Creed & Co Ltd Arrangement for receiving telegraph impulses
US2412350A (en) * 1943-05-10 1946-12-10 Curtis Engineering Company Multiple scale, multiple function instrument indicating system
US2478919A (en) * 1943-07-17 1949-08-16 Rca Corp Pulse type multiplex communication system
US2418116A (en) * 1943-12-20 1947-04-01 Standard Telephones Cables Ltd Multiplex synchronizing system
US2449467A (en) * 1944-09-16 1948-09-14 Bell Telephone Labor Inc Communication system employing pulse code modulation
US2451044A (en) * 1945-07-09 1948-10-12 Bell Telephone Labor Inc Communication system employing pulse code modulation
US2453461A (en) * 1946-06-19 1948-11-09 Bell Telephone Labor Inc Code modulation communication system
US2453454A (en) * 1946-08-31 1948-11-09 Bell Telephone Labor Inc Coder for code modulation transmission
US2603714A (en) * 1948-09-01 1952-07-15 Bell Telephone Labor Inc Percentage time division multiplex for pulse code modulation

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4179657A (en) * 1958-08-28 1979-12-18 The United States Of America As Represented By The Secretary Of The Air Force Anti-jamming communication system
US3030614A (en) * 1959-09-03 1962-04-17 Space General Corp Telemetry system
US3204030A (en) * 1961-01-23 1965-08-31 Rca Corp Acoustic apparatus for encoding sound

Also Published As

Publication number Publication date
NL150593B (nl)
NL106021C (sk)
CH297629A (de) 1954-03-31
DE830810C (de) 1952-02-07
BE492937A (sk)
GB679737A (en) 1952-09-24
FR1003982A (sk)

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